/*
*
* Original Javascript version by David Hedbor(http://www.bagley.org/~doug/shootout/)
*
*/

let function fib(n) {
    if (n < 2) return 1
    return fib(n-2) + fib(n-1)
}

local n = vargv.len()!=0 ? vargv[0].tointeger() : 1

println(fib(n))
